Method for establishing connection by hnb

ABSTRACT

The method for establishing a connection by a HNB comprising steps of: the HNB transmitting an “attachment request” message to an operation and maintenance center (OMC); the OMC transmitting an “attachment response” message to the HNB; the HNB establishing a connection with an MME indicated by the “attachment response” message. With the method proposed in the present invention, a UE can switch between HNBs in the same CSG through interface X 2 . Meanwhile, such information as the radio resource management and so on can be exchanged between two HNBs.

TECHNICAL FIELD

The present invention generally relates to communication technology,especially to a method for accessing a network by an HNB (home Node B).

BACKGROUND ART

A system structure of SAE is illustrated in FIG. 1. The system structureof SAE in FIG. 1 is described as following.

User Equipment 101 (hereinafter referred to as UE) is a terminal deviceused to receive data. 102 EUTRAN, also called ENB, is a radio accessnetwork of the LTE SAE, for providing interface through which an LTEmobile station accesses the radio network. Through interface S1, EUTRANconnects to a mobility management entity (MME) 103 and a user planeentity Serving Gateway 104 in the mobile station. 103 MME is adapted formanaging mobile context, session context for the UE, and holding userinformation on security. 104 Serving Gateway primarily provides afunction of user plane. An interface S1-MME is adapted for establishingradio access bearer, forwarding messages from UE to MME through awireless access network. The combination of 103 MME and 104 ServingGateway is similar to the original 106 SGSN (general packet radioservice (GPRS) supporting node). It is possible that both MME andServing Gateway locate at the same physical entity. 105 PDN Gateway isadapted for the functions like accounting, legally monitoring, etc. Andit is possible that both the Serving Gateway and the PDN Gateway locateat the same physical entity. 106 SGSN provides routing for datatransmission in existing UMTS. An existing SGSN finds a correspondinggateway GPRS supporting node (GGSN) according to an access point name(APN). 107 HSS is a home subscription sub-system for the UE and isadapted for storing user information such as the current location of UE,address of the serving node, security information on the user, activatedpacket data protocol (PDP) context for the UE and so on. 108 PCRFprovides QoS policy and accounting rules through interface S7.

In general, a user data stream reaches the 104 Serving Gateway through105 PDN Gateway. Then, through the GPRS tunnel protocol (GTP) channel,data is sent by the Serving Gateway to the ENB where the UE locates in,and now it is sent by the ENB to corresponding UE.

HNB refers to a Node B applied in a home. It also can be applied in suchsite as a university, a company and so on. HNB is a plug and playdevice. Difference between an HNB and a general macro node B is that: ingeneral not all UEs can access an HNB. For example, only the UEs in auser's home or that are allowed to access the HNB can access thecorresponding HNB. And for the HNB in a company, only the company'sstaff and its allowed partners can access the HNB. The HNB group (e.g.,the HNB in a company) bearing the same access subscriber cluster iscalled CSG (closed subscriber group). No interface X2 (interface betweenNode Bs in SAE) exists between general HNBs (e.g., the HNBs in homes) orbetween an HNB and a macro Node B. Through interface S1, a UE switchesbetween HNBs or between an HNB and a macro Node B.

For an HNB applied in a company or university or the like, a UEfrequently moves between two HNBs in the same company. In this case, theswitch is always implemented through interface S1 so that great delaycauses and efficiency is very poor. In addition, information such asradio resource management and so on can not be exchanged between twoHNBs in the same company so that resources can not be utilizedeffectively.

DISCLOSURE OF INVENTION Technical Problem

The object of this invention is to provide a method for establishing aconnection by a Home Node B HNB.

Technical Solution

To achieve the object mentioned above, a method for establishing aconnection by a HNB comprising steps of:

the HNB transmitting an “attachment request” message to an operation andmaintenance center (OMC);

the OMC transmitting an “attachment response” message to the HNB;

the HNB establishing a connection with an MME indicated by the“attachment response” message;

With the method proposed in the present invention, a UE can switchbetween HNBs in the same CSG through interface X2. Meanwhile, suchinformation as the radio resource management and so on can be exchangedbetween two HNBs.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more apparent from the following detailed descriptionin conjunction with the accompanying drawings, in which:

FIG. 1 shows a network structure of SAE;

FIG. 2 shows a process that a connection is established for HNB inembodiment 1 of present invention;

FIG. 3 shows the process that a connection is established for HNB inembodiment 2 of present invention;

FIG. 4 shows an operation flows at HNB according to embodiment 1 andembodiment 2 respectively;

FIG. 5 shows an operation flows at OMC according to embodiment 1 andembodiment 2 respectively;

FIG. 6 shows an operation flows at MME according to embodiment 1 andembodiment 2 respectively; and

FIG. 7 shows a process of reconfiguring MME or S-GW.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment 1 of the present invention is illustrated in FIG. 2.Following is a detailed description with reference to FIG. 2. Detailedtechnical description for the known components is omitted. In thisembodiment, within a CSG, HNB1 is a first HNB that accesses the network.

MODE FOR THE INVENTION

In Step 201, HNB1 transmits an “attachment request” message to the OMC.This message contains information on a location of the HNB. Optionally,the “attachment request” message contains an identifier of the CSG towhich the HNB belongs. Optionally, the network assigns the CSGidentifier to HNB (the first HNB or the first group of HNBs within theCSG) when HNB signs in, or knows the identifier of the CSG to which theHNB (not the first signed in group of HNBs in the CSG) belongs when HNBsigns in.

-   -   In Step 202, OMC selects an MME for the HNB. Within the CSG, the        HNB is the first one that accesses the network. OMC selects an        MME for it among the MMEs adjacent to the HNB according to a        certain rule such as for balancing the load, reducing a        possibility of changing MME when UE moves, and so on.        Optionally, OMC may select an S-GW for the HNB according to the        same rule as on the selection of MME. HNB and OMC check other        HNBs in the CSG which need to establish X2 connection with the        HNB. According to the CSG identifier, OMC checks other HNBs in        the CSG which need to establish X2 connection with the HNB.        Optionally, the addresses of the HNBs are considered when OMC        checks other HNBs in the CSG which need to establish X2        connection with the HNB. For example, it is not necessary to        establish interface X2 between two HNBs if the two HNBs that are        in different countries but in the same company belong to the        same CSG. In this embodiment, no other HNB exists in the CSG.

The process of selecting S-GW for HNB can be implemented by the MMEconnected to the HNB when data is transferred through the HNB.Therefore, the HNBs in the same CSG connect to the same S-GW. If it isnecessary for the first HNB in the CSG to establish the user plane, MMEselects an S-GW for the CSG according to such rules as to balance loador to reduce the possibility of changing S-GW when a UE moves, and soon.

In Step 203, OMC transmits an “attachment response” message to the HNB.This message indicates the MME selected by the OMC for the HNB.Optionally, this message indicates other HNBs necessary to establish X2connection and adjacent to the HNB. Optionally, the message contains thefrequency for using the HNB. The “attachment response” message containsthe information on adjacent cells. The “attachment response” messagecontains a track area identifier (TAI) for the HNB. The “attachmentresponse” message contains the identifier assigned to the HNB.Optionally, the message contains an address of the S-GW that OMCselected for the HNB.

In Step 204, HNB initiates a process to establish a connection with theMME indicated by the message. HNB transmits a “connection request”message to MME. The message contains the information on “cells which areoverlapped with HNB or CSG”. Optionally, the message contains aninformation element of the identifier of the TAI where HNB locates in.Optionally, the message contains the information element of theidentifier of HNB. Optionally, the message contains the informationelement of the identifier of the CSG where HNB locates. MME transmits a“connection response” message to HNB.

Embodiment 2 of the present invention is illustrated in FIG. 3.Following is detailed description to the figure. Detailed technicaldescription for known components is omitted. In this embodiment, HNB1and HNB2 belong to the same CSG. HNB1 has accessed the network. And HNB2begins to accessing the network for a first time.

In Step 301, HNB2 transmits the “attachment request” message to the OMC.This message contains the information on the location of HNB2.Optionally, the “attachment request” message contains the identifier ofthe CSG to which the HNB2 belongs. Optionally, the network knows theidentifier of the CSG to which the HNB belongs when HNB signs in.

Step 302, OMC selects an MME for the HNB. If the HNB is not the first toaccess the network in the CSG, the MME selected by OMC for other HNBs inthis CSG is just the one that the HNB should connect to. In thisembodiment, OMC assigns both the MME and the S-GW selected for HNB1 tothe HNB. Optionally, the address the HNB should be considered when OMCselects MME for the HNB. For example, if two HNBs that are in differentcountries but in the same company belong to the same CSG, they may notbe able to connect to the same MME. In this case, if no adjacent HNBaccesses the network, OMC thinks that this HNB is the first one whichaccesses the network in the CSG and selects an MME for it according torules such as balancing load or reducing possibility of changing MMEwhen a UE moves, and so on. Optionally, selection of S-GW for the HNBcan be implemented by OMC according to the same rules on the selectionof MME. OMC checks other HNBs in the CSG which need to establish X2connection with the HNB. And according to the CSG identifier, OMC checksother HNBs in the CSG which need to establish X2 connection with theHNB. Optionally, the addresses of the HNBs, as well as whether the HNBsshare the same CSG or not, are considered when OMC checks other HNBs inthe CSG which need to establish X2 connection with the HNB. For example,it is not necessary to establish interface X2 between two HNBs if thetwo HNBs that are in different countries but in the same company belongto the same CSG. In this embodiment, for example, it is necessary toestablish X2 connection between HNB1 and HNB2.

The process of selecting S-GW for HNB can be implemented by the MMEconnected to the HNB when data is transferred through the HNB.Therefore, the HNBs in the same CSG connect to the same S-GW. If it isnecessary for the first HNB in the CSG to establish the user plane, MMEselects an S-GW for the CSG according to such rules as to balance loador to reduce the possibility of changing S-GW when a UE moves, and soon. If the HNB is not the first necessary to establish a user plane inthe CSG, the S-GW selected by MME for other HNBS in this CSG is just theone that the HNB should connect to.

In Step 303, OMC transmits the “attachment response” message to theHNB2. This message indicates the MME that the OMC selected for the HNB.And the MME information included in the message may be the IP address ofthe MME. Optionally, this message contains a list of other HNBsnecessary to establish X2 and adjacent to the HNB. The HNB listinformation included in the message is an IP address list for the HNB.Optionally, the message contains a frequency for using the HNB. The“attachment response” message contains the information on adjacentcells. The “attachment response” message contains the track areaidentifier (TAI) for the HNB. The “attachment response” message containsthe identifier assigned to the HNB. Optionally, the message contains theaddress of the S-GW that OMC selected for the HNB.

In Step 304, HNB2 initiates a process to establish a connection with theHNB indicated by the message. HNB2 transmits the “connection request”message to the other HNB (e.g., HNB1). HNB1 transmits the “connectionresponse” message to HNB2.

In Step 305, HNB2 initiates a process to establish a connection with theMME indicated by the message. HNB2 transmits the “connection request”message to MME. The message contains the information on “cells which areoverlapped with the HNB or CSG”. The message contains the informationelement of the identifier of the TAI where HNB locates. Optionally, themessage contains the information element of the identifier of HNB.Optionally, the message contains the information element of theidentifier of the CSG where HNB locates. MME transmits the “connectionresponse” message to HNB2.

The sequence of performing step 304 and step 305 is not limited.

In this embodiment, the operation flow of HNB is illustrated in FIG. 4.Here, detailed technical description for known components is omitted.

In 401, HNB transmits the “attachment request” message to the OMC. Thismessage contains the information on the location of HNB. Optionally, the“attachment request” message contains the identifier of the CSG to whichthe HNB2 belongs. In 402, HNB waits for the response message. In 403, ifHNB receives a “successful attachment response” message, it saves theinformation that is included in the message, such as information on MMEand the information on other HNBs, TAI, the HNB identifier and so on. In404, HNB initiates the process to establish a connection with the MMEindicated by the message. HNB transmits the “connection request” messageto MME. Optionally, the message contains the information on “cells whichare overlapped with the HNB or CSG”. Optionally, the message containsthe information element of the identifier of the TAI where HNB locates.Optionally, the message contains the information element of theidentifier of HNB. Optionally, the message contains the informationelement of the identifier of the CSG where HNB locates. MME transmitsthe “connection response” message to HNB. 405 Optionally, if the“attachment response” message contains information on other HNBs, suchas HNB IP address list, HNB initiates the process to establishconnections with other HNBs. HNB transmits the “connection request” toanother HNB. An another HNB transmits the “connection response” messageto the HNB.

The sequence of performing step 404 and step 405 is not limited.

In this embodiment, the operation flow of OMC is illustrated in FIG. 5.Here, detailed technical description for known components is omitted.

In 501, OMC receives messages. In 502, if OMC receives the “attachmentrequest” message from HNB, in 503 it saves HNB related information. Andif the message contains the location information for HNB, OMC saves thisinformation. And if the message contains the identifier of the CSG wherethe HNB belongs, OMC saves this information.

In 504, if the HNB is the first to access the network in correspondingCSG, in 505, OMC selects an MME for HNB in this CSG. OMC selects the MMEaccording to either the address of HNB, or the rule to balance load orto reduce the possibility of changing MME when a UE moves, etc.Optionally, OMC can select an S-GW for the HNB according to the samerule as on the selection of MME.

In Step 506, if HNB is not the first to access the network in the CSG,507 OMC checks other HNBs in the CSG. 508 OMC transmits the “attachmentresponse” message to the requesting HNB. And information on the MME OMCselected for HNB in this CSG is included in the message. Optionally, the“attachment response” message contains the information on the S-GWselected by OMC for HNB in this CSG. Optionally, the message containsthe information on other HNBs in this CSG, such as the IP address listfor the HNB. Optionally, the message contains the identifier of the TAIwhere the HNB locates. Optionally, the message contains the HNBidentifier allocated to the HNB. The case described above is for thatthe HNBs in the CSG are not far away from one another. In another case,for example, two HNBs belong to the same CSG in different countries butin the same company, if no adjacent HNB accesses the network, OMC thinksthat this HNB is the first one which accesses the network in the CSG andselects an MME for it according to such rules as to balance load or toreduce possibility of changing MME when a UE moves, and so on.Optionally, OMC can select an S-GW for the HNB according to the samerule as on the selection of MME. In this case, OMC finds the other HNBis the one necessary to establish a X2 connection with the HNB in theCSG according to not only the CSG ID. Meanwhile, it should consider thelocation of the HNB. For example, it is not necessary to establishinterface X2 between two HNBs if the two HNBs that are in differentcountries but in the same company belong to the same CSG.

In this embodiment, the operation flow of MME is illustrated in FIG. 6.Here, detailed technical description for the known components isomitted.

In 601 MME receives messages. In 602 if MME receives the “connectionrequest” message from HNB, in 603 MME saves the information which isincluded in this message, such as the information on “cells which isoverlapped with the HNB or CSG”, the identifier of the TAI where HNBlocates, the HNB identifier. 604 MME transmits the “connection response”message to HNB.

FIG. 7 illustrates the process that OMC reconfigures CSG's MME or S-GWwhen overload or fault comes across the MME or the S-GW.

In Step 701, OMC finds that overload or fault comes across the MME orS-GW connected to a certain CSG.

In Step 702, OMC transmits a “reconfiguration request” message to theHNB in CSG. In this message, the information on the reconfigured MME orS-GW and the reason for the reconfiguration are included. And thereconfiguration can be done to the IP address of the MME or the S-GW.

In Step 703, the HNB that has received the “reconfiguration request”message transmits the “connection request” message to the new MME orS-GW. Optionally, the “connection request” message sent to MME includesthe information on “cells which are overlapped with the HNB or CSG”.Optionally, the “connection request” message sent to MME contains theinformation element of the identifier of the TAI where HNB locates. Thenew MME or S-GW transmits the “connection response” message to the HNB.

In Step 704, the HNB transmits a “reconfiguration response” message toOMC.

Optionally, if the reconfiguration results from the overload of MME orS-GW, HNB initiates the process of releasing the connection withoriginal MME or S-GW.

INDUSTRIAL APPLICABILITY

While the invention has been shown and described with reference tocertain exemplary embodiments of the present invention thereof, it willbe understood by those skilled in the art that various changes in formand details may be made therein without departing from the spirit andscope of the present invention as defined by the appended claims andtheir equivalents.

1. A method for establishing a connection by a HNB, the methodcomprising: transmitting, by the HNB, an “attachment request” message toan operation and maintenance center (OMC); transmitting, by the OMC, an“attachment response” message to the HNB; and establishing, by the HNB,a connection with an MME indicated by the “attachment response” message.2. The method according to claim 1, wherein the “attachment request”message contains an identifier of a CSG where the HNB locates.
 3. Themethod according to claim 1, wherein the “attachment request” messagecontains information on location of the HNB.
 4. The method according toclaim 1, wherein if the HNB is a first one to access the network in aCSG, the OMC selects an MME for this HNB.
 5. The method according toclaim 1, wherein the “attachment response” message contains informationon the MME selected by OMC for the HNB.
 6. The method according to claim1, wherein the “attachment response” message contains information onother HNBs necessary to establish X2 and adjacent to the HNB.
 7. Themethod according to claim 1, wherein if the HNB is a first one to accessthe network in a CSG, OMC selects an S-GW for this HNB.
 8. The methodaccording to claim 1, wherein if the HNB is a first one to access thenetwork in a CSG in a certain area, OMC selects an MME for this HNB. 9.The method according to claim 4, wherein that the OMC selects MME orS-GW according to the location of the HNB.
 10. The method according toclaim 4, wherein that OMC selects MME or S-GW according to loadbalancing.
 11. The method according to claim 4, wherein the OMC selectsMME or S-GW according to a rule of reducing possibility of changing MMEor S-GW when a UE moves.
 12. The method according to on claim 1, whereinif the HNB is not a first one to access the network in the CSG, the MMEor S-GW selected by OMC for other HNBs in this CSG is just the one thatthe HNB should connect to.
 13. The method according to claim 6, whereinthe OMC obtains adjacent HNBs necessary to establish X2 with the HNBaccording to an identifier of the CSG where the HNB locates.
 14. Themethod according to claim 13, wherein OMC obtains the adjacent HNBsnecessary to establish X2 with the HNB according to the location of theHNB.
 15. The method according to claim 1, further comprising:establishing, by the HNB, connections with other HNBs indicated by theattachment response message.
 16. The method according to claim 1,wherein the “attachment response” message contains information on theMME to which the HNB in a CSG connects.
 17. The method according toclaim 16, wherein the information on the MME to which the HNB in the CSGconnects is an IP address of the MME.
 18. The method according to claim1, wherein the “attachment response” message contains the information onthe S-GW to which the HNB in a CSG connects.
 19. The method according toclaim 18, wherein the information on the S-GW to which the HNB in theCSG connects is an IP address of the S-GW.
 20. The method according toclaim 1, wherein the “attachment response” message contains informationon other HNBs in the CSG.
 21. The method according to claim 20, whereinthe information on other HNBs in the CSG is an IP address list of theHNB.
 22. The method according to claim 1, wherein the establishing ofthe connection between HNB and MME comprising: transmitting, by the HNB,a “connection request” message to the MME; and transmitting, by the MME,a “connection response” message to the HNB.
 23. The method according toclaim 22, wherein the connection request message contains an HNBidentifier.
 24. The method according to claim 22, wherein the connectionrequest message contains an identifier of the TAI where the HNB locates.25. The method according to claim 22, wherein the connection requestmessage contains information on “cells which are overlapped with the HNBor CSG”.